There is a popular
superstition in western
culture that a
Friday falling on the thirteenth day of a month is especially likely to be unlucky. Some say this is because there were thirteen people at the Last Supper before
Jesus was put to death.
However, the truth is far stranger. In the prehistory of man, according to a book I read in high school, people counted on their fingers and feet. This meant that they could only count to 12; 13 - and all higher numbers - were part of the uncountable unknown, something that no human wants to contemplate!